论文部分内容阅读
结合双向间歇电磁搅拌与低过热度浇注复合工艺制备了凝固组织、拉伸性能较为理想的半固态A356-0.5Ce(质量分数)合金铸锭,通过OM分析铝熔体施加不同搅拌方式(无搅拌、30Hz单向连续电磁搅拌以及30Hz双向间歇电磁搅拌)对初生α相晶粒尺寸和形态的影响规律。结果表明,在30 Hz双向间歇电磁搅拌条件下初生晶粒细化球化程度较好,平均等积圆直径为35.9μm,形状因子为0.79。利用SEM研究了3种搅拌方式下合金铸锭的拉伸性能与断口形貌。相较于常规铸造,30Hz单向连续电磁搅拌和30 Hz双向间歇电磁搅拌作用下合金的抗拉强度由125 MPa分别增至143、176 MPa;延伸率由4.2%增至5.4%、7.8%,断裂机制由脆性解理断裂过渡为韧性断裂。
A semi-solid A356-0.5Ce alloy ingot with solidified microstructure and good tensile properties was prepared by the combination of two-way intermittent electromagnetic stirring and low superheat pouring. The OM melt was analyzed by OM with different stirring methods , 30Hz one-way continuous electromagnetic stirring and 30Hz two-way intermittent electromagnetic stirring) on the primary α-phase grain size and morphology. The results show that the grain refinement of primary grains is better under the condition of 30 Hz bidirectional intermittent electromagnetic stirring. The average equivalent circle diameter is 35.9 μm and the shape factor is 0.79. The tensile properties and fracture morphology of alloy ingot under three kinds of stirring methods were studied by SEM. Compared with the conventional castings, the tensile strength of the alloys increased from 125 MPa to 143,176 MPa respectively under the conditions of 30Hz unidirectional continuous electromagnetic stirring and 30 Hz bidirectional intermittent electromagnetic stirring; the elongation increased from 4.2% to 5.4% and 7.8% Fracture mechanism transition from brittle cleavage fracture to ductile fracture.